Recently, in accordance with development of a communication environment, it is necessary for an individual user to remember a large number of identification information (e.g. ID) and authentication information (e.g. password) that should be remembered by the user, or remember communication identification information (e.g. mobile phone number, work phone number, home phone number, work fax number, etc.), and remember Internet identification information (e.g. website address, social network ID, URL address, e-mail ID, etc.), thereby resulting in inconvenience.
Further, in an environment in which such heterogeneous communication devices are in everywhere, the user should remember various identification information (ID or phone number) of other people as well as identification information of the user, and in a case of a mobile phone, if the user has forgot a phone number of an acquaintance, the user may lose contact with the acquaintance when the phone number thereof is changed during an out-of-contact period.
Meanwhile, even when the acquaintances of the user give their identification information one by one, since the user needs to record the identification information of the acquaintances in an address book of a smartphone or an address book of e-mail, it is cumbersome and inconvenient to input the information, and it is also cumbersome and time-consuming to inform the acquaintance of identification information of various heterogeneous devices of the user.